Electrical multiple relay unit using sealed reed contacts



A ril 17, 1962 J. J. DONCEEL ETAL 3,030,468

ELECTRICAL MULTIPLE RELAY UNIT USING SEALED REED CONTACTS Filed June 2, 1958 In 8" OHS Imam/am M.Mu5

Attorney United States Patent Ofiice 3,030,458 Patented Apr. 17, 1962 3,030,468 ELECTRICAL MULTIPLE RELAY UNIT USING SEALED REED CONTACTS Jules Louis Joseph Donceel and Marnix Mus, Antwerp, Belgium, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed June 2, 1958, Ser. No. 739,277 Claims priority, application Netherlands July 25, 1957 4 Claims. (Cl. 20087) The invention relates to an electrical multiple relay unit using sealed reed contacts.

Sealed reed contacts have in themselves been known for a long time already, and a particular construction is described in the U.S. Patent No. 2,289,830.

Relay units providing for a plurality of sealed reed contacts surrounded by a single coil are also disclosed in the above patent as well as in the U.S. Patent No. 2,39 ,123. Also, several reed contacts inside a single evacuated vessel surrounded by a common coil are shown in the U.S. Patent No. 2,535,400.

An object of the invention is to realize an electrical multiple relay unit using sealed reed contacts which may constitute the equivalent of several relays, which may be operated or not in various combinations and held operated by means common for all the contacts.

More particularly, the invention relates to such a unit as defined above and comprising a plurality of elongated sealed reed contacts each of which may be influenced by at least two magnetic fields.

Such an arrangement is to be found in the U.S. Patent No. 2,187,115 where each sealed reed contact vessel is surrounded by two coils whereby the two magnetic fields respectively produced by said coils are jointly responsible for the closure of the contact. The contact devices and coils may be so constructed and the energizing current may be so adjusted that a connection will be maintained between the contacts in a vessel after one of these coils is de-energized and the energization of the other coil is reduced to as low as 50% of its original energizing value. Control by twomagnetic fields is also to be found in the U.S. Patent No. 2,243,399 for the purpose of closing the various contacts in sequence. In U.S. Patent No. 2,187,115 the purpose is to realize the equivalent of a crossbar switch, while in U.S. Patent No. 2,243,399 the aim is to produce the equipment of a stepby-step marking switch.

In accordance with a characteristic of the invention, a unit as defined above consists in a common device such as a coil or a permanent magnet and in a plurality of individual coils each wrapped around one or more sealed reed contacts, with their axes parallel to and equidistant from the axis of said common device, and said common device is or may be adapted to generate a magnetic field insuflicient to cause the displacement of any of said contacts, but sufficient to hold one or more of said contacts displaced in an operated position once they have been operated with the help of the magnetic field(s) produced by the corresponding individual cil(s).

It is to be noted that the use of a permanent magnet for the common holding device is a very useful alternative when no power source is available at the place where the relay unit is located. The latter may then be operated by distant pulses, and released in an analogous manner for instance by providing additional windings on the individual reed contact units, or by providing a coil mounted on the permanent magnet.

The use of permanent magnets to influence sealed reed contact units is in itself not new as it is disclosed in the U.S. Patent No. 2,289,830. in this patent, the magnet is outside the evacuated vessel and a key arrangement permits the displacement of the magnet and the operation of the inside contacts. A magnetic core is also incorporated inside the vessel of the arrangement disclosed in the U.S. Patent No. 2,264,022, and magnetic circuits outside the sealed units are also to be found in the U.S. Patent No. 2,397,123. In the vibrating reed selector disclosed in the U.S. Patent No. 2,694,119 and which is a different kind of arrangement, controlled by A.C. energy, a magnet is also proposed for locking vibrating tuned reeds once they vibrate with a sufficient amplitude. An opposing magnetic field is also suggested to permit the release of the vibrating reeds.

Another object of the invention is to minimize the size of an electrical multiple relay unit of the type defined above.

In accordance with another characteristic of the invention, the common holding device is surrounded by the plurality of individual coils.

Yet another object of the invention is to maximize the effect of the common device.

In accordance with yet another characteristic of the invention, said common device and eventually said individual coils, is or are surrounded by one or more closely fitting magnetic material members which extend over such a part of the length of said common device that the magnetic field which it produces or is made to produce, has an increased or preferably maximum effect on the operation of the desired contacts.

Apart from enhancing the efiect of the common cen- -tral coil, the additional magnetic material member acting as a flux concentrator otters also the advantage that it diminishes mutual interference between the various individual contact units. This is due to a low reluctance central common path being provided which is such that displacement of a particular set of contacts will have a negligible effect on the overall reluctance, and it will therefore hardly affect the operation of the other individual contacts. This feature is in itself already disclosed in the U.S. Patent No. 2,397,123 where a magnetic strip is provided outside the coil surrounding the evacuated contactv vessel, this strip being connected to one contact at one end and narrowly spaced from the other contact at its other end.

The above and other objects of the invention will be better understood from the follownig description of a detailed embodiment thereof to be read in conjunction with the accompanying drawing wherein:

' FIG. 1 shows a sectional side-view of a unit in accordance with the invention and through a plane including its central axis;

FIG. 2 shows a plan view of an alternative to the flux concentrator member shown in FIG. 1; and

FIG. 3 shows a schematic plan view of a way in which the individual contact units can be arranged with corresponding terminals to form the complete multiple unit.

Referring to FIG. 1, the multiple unit shown consists in a central cylindrical core 1 on which is mounted a corresponding winding 2. This central core 1 is partially shielded by two flux concentrator members 3 and 3' which are shaped as cylinders opened at one end and oppose each other towards the inside of the unit, and made out of suitable magnetic material. A plurality,

e.g. six, of cylindrical sealed reed contact units of which- "efiectis, derived from the central, coil arrangement.

7-7. These reeds 7-7' slightly overlap in the middle,

of the unit to form a front contact which can be closed under the influence of a suitable magnetic field. To the flux concentrator members 3 and 3 are fixed the spool heads 8-'8' made of suitable insulating material and pierced by suitable apertures such as 9 to permit the open ends of the reeds to be inserted'and held'therein; Central screws 1010' are used to secure these spool heads to the members 3--3'. As shown, the lower spool head 8 may be made somewhat larger than the upper spool head 8 for the purpose of mounting terminals such as 11 to which may be connected the ends of the windings such as 2 and 5, as well as the ends of wires having their other ends connected to the upper reeds such as 7. In this manner, all external electrical connections can be made on one side of the multiple unit.

The ampere-turns which may be developed by the central common winding 2 are used not only for the purpose of holding one or more reed contacts operated, but also to help in operating them. In this manner, the various contacts may be operated in ditferent combinations by pulses supplied over corresponding signalling leads. In such a case, the maximum ampere-turns allowed to be developed by the central winding 2. are determined by considering that these ampere-turns alone cannot operate any of the individual contacts. On the other hand, the minimum ampere-turns to be developed by the central winding 2 are determined by that individual contact which it is most easy to release once it has been operated by a I pulse through its corresponding winding acting in conjunction with the ampere-turns developed by thecentral' winding. Tests have shown that a good margin can be secured between these maximum and minimum ampereturns for the central winding, eventhough the. individual. contacts may have different sensitivities, despite, the fact that they are all at the same distance from the central winding 2. For example, with a ratio of.' the order of. two or more between the maximum and the minimum ampereturns for the common winding 2, there willbe no difliculty in selecting a nominal intermediate value, e.g, thev geometric means, which will suitably take care of various tolerances. These are. the tolerances allowed on the number of turns of the individual windings, the tolerance on the D.C. resistance of these windings, and the tolerance on the supply voltage from which the energizing pulses are derived.

Other considerations which may govern the. choice of the intermediate ampere-turns value for the. central. coil 2 are the minimum pressure needed to close the individual sets of contacts to prevent undesired closures, the min,- imum pressure needed to open a closed set of contacts when it is held under the control of the centralcoil, and the maximum D.C. resistance of a closed set of contacts held under the control of this common winding. Tests have permitted to verify that these two pressures as well as the resistance all increase, when the common ampereturns aredecreased.

It should be remarked that the location of the common holding device at the center at the arrangement is particularly advantageous in that it permits to secure a multiple unit of overall reduced size by using inside space which is inevitably present once three individual units or more are arranged in circular fashion around a central axis. The diameter of the central cylindrical, space of course increases as the number ofv units increases to become equal to the diameter of the cylindrical space taken by an individual unit when six of these are used, and becoming larger than this last diameter for a greater. number of units.

As shown in FIG. 1, the axial length of. the two flux concentrator members 3-3' is chosen so that a maximum A shorter length would. reduce the effect, andon the other hand greater length would lead to a complete magnetic short-circuit. As shown, the flux concentrator members extend over a substantialpart of the length, of the individual units except along their central parts where the two contact reeds form an airgap which should not be shortcircuited.

The pulse concentrator elements 33' shown in the FIG. 1 may evidently be designed in various ways and the choice will be determined by manufacturing considerations.

FIG. 2 shows an alternative embodiment of the flux concentrator elements which maybe produced from a sheet of suitable material cut as shown in the case of'six individual sealed reed units. A central hole 12 is provided for fixing the flux concentrator, and holes such as 13 are made to permit the reed contacts to go through the concentrator elements. Turned-up legs 14' are then made of a suitable length to provide a cylindrical arrangement open atone endand similar to that shown in FIG. 1. The main distinction is however that the concentrator elements: do not completely enclose the. central coil 2 since openings remain between the legs. 14. On the other hand, the element now surrounds not only the central coil but also the individual reed units. This arrangement has beenfound to be: somewhat more; efiicient than using a flux concentrator element. which is; inside the. individual units, but withthe latter. arrangement,.the efiect is already substantial, sov thattheconstruction: of FIG. 2 may also be made with a smaller. diameter whereby the legs; 14 shown in dotted lines::would: remaininside the array of individual: contact units;

FIG. 3 shows. schematically how six. units can be arranged around the centralholding device'when the latter has a diameter somewhat larger than the: diameter of the individual cylindricalgunits. In such a case, if the number of individual units is not such that they needbe contiguous. to one another along the outside circumference, they need not essentially be evenly spaced; As. shown in FIG. 3, while they remain equidistant from" the center of the multipleunit, they can be packed in two groups to=permit a convenient rectangular cross-section for thespool-heads which will enable efiicient mounting ofthe multiple units. Mounted as shown, the individual units; are nearer to onev another than they need be, but. as mutual interference is slight, especially in view of the magnetic parallel path provided by the flux concentrator, this v presents no drawback.. The rectangles 15, 15 represent terminals to. which individual windings 5 may be attached by their ends, and rectangles 16 represent terminals towhich reed 7 may be electrically connected.

While the principles of the invention'have been de scribed above in connection with specific apparatus, it is to be clearly understood. that this description is made only by way of example and not as a limitation on the scope of the invention.

What is claimed is:

1. An electrical switching apparatus comprising a central coil, concentrating means encircling a portion of the coil for concentrating the magnetic flux generated by said coil when energized around a given. area thereof, a plurality of separate sealed reed contacts made of magnetic material and disposed around said coil outside of the periphery of the concentrating means, said reed contacts having their axes parallel to and equidistant from the axis of said central coil and having their operating portions in register with said given area, a plurality of separate windings, each cooperating with a ditferent one of said reed contacts, the flux developed by any of said separate windings when energized being insufficient to actuate the associated reed contacts unless said central coil is energized, the flux developed by said central coil when energized being. suflicient to maintain operated actuated reed contacts after de-energization of their associated windings.

2. An electrical switching apparatus as claimed in claim 1, further comprising a pair of spaced mounting plates,

said central coil and said separate sealed reed contacts mounted between said plates.

3. An electrical switching apparatus as claimed in claim 1, wherein said concentrating means comprises a pair of cup-shaped elements made of magnetic material, each element extending coaxi-ally over a portion of said central coil from an opposite end thereof, the space between the open ends of said elements comprising said given area.

4. An electrical switching apparatus as claimed in claim 1, wherein said concentrating means comprises a multiarmed spider element having a plurality of arms extending in planes transverse to the plane of said element, each arm being in proximity to a difierent one of said sealed reed contacts.

References Cited in the file of this patent UNITED STATES PATENTS 2,l=87,ll5 Ellwood et al Ian. 16, 1940 2,318,405 Leveridge May 4, 1943 2,397,123 Brown Mar. 26, 1946 2,821,597 Germanton et al Ian. 28, 1958 2,836,676 Wirth May 27, 1958 2,902,558 Peek Sept. 1, 1959 

